


Undersidious ARC 2

by orphan_account



Series: Undersidious [2]
Category: Undertale (Video Game)
Genre: Cliffhangers, F/F, Gen, Papyrus is a sociopath, Sans is misguided, Undyne is mad, Undyne the Undying - Freeform, fight, yes - Freeform
Language: English
Status: Completed
Published: 2017-05-06
Updated: 2017-05-06
Packaged: 2018-10-27 17:24:52
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings, Major Character Death
Chapters: 4
Words: 4,574
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10813470
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: Arc 2 is here! Yay! Check out the first arc please before you read this one.





	1. Arc 2 Chapter 1

**Arc 2 Chapter 1**

 

Recap:

 

"I know you guys that well. I know what you would or wouldn't do and to what lengths you'd go to do such things. So to make things shorter, my guess _is...," Frisk starts and pause for dramatic affect._

 

_There's a tense silence as everyone is on edge and shifting nervously, being put on the spot and all. Nobody would want to be called out on attempting to murder the Ambassador of Monsters. Especially if they are all monsters._

 

_"None of you."_

 

_"Huh?"_

 

_*_

 

_He raises his weapon and slams it down with enough force to instantly shatter Frisk's dull red soul. Forever. Frisk will not be coming back. He will not allow such a thing. Then, just as quickly as he came, he leaves._

 

_*_

 

_He whispers to the gravestone, "So Frisk, how's it like being the one dead for a change when you had done nothing wrong? Do you finally understand? I'm not quite what you thought me to be, was I?"_

 

_"papyrus, come on. we should get going now," Sans calls from a little bit away._

 

_"OKAY!" the figure responds before getting up and leaving the gravesite behind._

 

_ _ _ _ _ _ _ _

 

Papyrus and Sans are exiting the cemetery when Papyrus spots a patch of Echo Flowers. Papyrus thinks for a moment. He informs Sans loudly, "SANS, I'M GOING TO GO DO SOMETHING! WHY DON'T YOU VISIT FRISK, BROTHER?!"

 

Sans smiles -- as if he had a choice -- and nods in agreement, "good idea, bro."

 

Papyrus walks away as Sans walks towards the graveyard. He abruptly stops a few minutes later in a location away from any others. A little, yellow flower pops up. This little guy always seems to know everything. He does. He knows more about Papyrus in particular. His grin is wide and evil.

 

"I know what you did," Flowey claims boldly.

 

"WHAT DID I DO, FLOWEY?" Papyrus asks, willing to let others assume he's oblivious.

 

"Oh, don't play dumb. You must love seeing the others suffering. You're smart. You know to take out the one that has affected them the most," Flowey explains.

 

"How did you find out?" Papyrus inquires, truly curious even if he knows that Flowey always knows. Flowey _always_  knows.

 

"Oh, I have my ways," Flowey informs. And it's true. Flowey is always able to sneak around unseen by everyone else. Whether it's actual stealth or that he knows how to use his small stature to his advantage, Papyrus isn't sure. It's probably both though.

 

"Of course," Papyrus agrees.

 

"So what's the real reason, Papyrus? Why did you kill Frisk?" Flowey asks, clearly wanting a straight answer.

 

"I'm a sociopath."

 

"Are you sure? When Frisk would kill anyone, you seemed pretty determined to not kill them, and even after dying, you would believe in them," Flowey questions his statement.

 

"I needed to test their guilt," Papyrus says blandly.

 

"I see. You're going to kill all of them now, right?" Flowey asks, but it's more of a suggestion from one heartless monster to another.

 

"I'll think about it," Papyrus says.

 

Elsewhere, Sans had heard all of it. His brother… Did he mess up? What happened to the innocent, nice Papyrus that believed in everyone? What happened to the Papyrus that would make spaghetti and be happy about even if it wasn't that good? What happened to the Papyrus that was determined to get into the Royal Guard even if he had no hope of doing so? What happened to his little brother? What happened?

 

Then, he remembers what the whole conversation was about. The human. Frisk. The pacifist. The Ambassador of Monsters. The one who freed them all. The one who had still been a little gray and internally bleeding from dying and resetting during their time in the Underground. The one that even though he hated them for their mistakes, he forgave them after they stopped resetting finally. Papyrus killed them. Papyrus, of all people. Of all monsters. He didn't want to think it possible, but Papyrus and Flowey both casually talked about it like the weather.

 

He really needs to sit down. He wishes he hadn't heard that. He really does. He wants to pretend like he just heard it all wrong. Like he misinterpreted their words. Like they had been joking about it. Like they had been doing some sick roleplay. Like they were lying. But Papyrus's indifference to it all was frightening. What does he do?

 

He wonders if he should've just waited until later to ask Papyrus that question. He was going to ask Papyrus if he thought he should ask Toriel to date him. He supposes he wouldn't care. Now that he thinks about it now, that would probably be a terrible idea. Toriel seems to be getting along with Asgore again. Anyways, it would ruin their friendship. Not to mention, Toriel is still upset about Frisk. It would be too soon and very insensitive. He doesn't want to take advantage of her in such a vulnerable time.

 

He sighs and looks to his feet. What would Frisk say? Maybe something about looking on the bright side? What'd be the bright side? Papyrus isn't dead. He's not sure if that's a good thing. Should he be angry at Frisk for pushing Papyrus over the edge or Papyrus for killing Frisk? He's, at this point, just a bundle of pent up emotions that just want to escape but can't. He wants to get away. Can he run away from his problems? Yes. Can he hide from them? Not these ones.

 

So Sans runs away. He just runs. As much as it goes against his morals of being as lazy as possible, he can't be inactive while his demons are chasing him. He just needs to get away. Somehow. He doesn't care where he ends up as long as it's away from all these problems and emotions. Maybe Grillby's. Or his bed. His bed seems really nice right now. Maybe he could just sleep the day away. That's really appealing.

 

Then, he runs into something. Or rather someone. Tall. Blue. Red hair. Strong smell of fish and… instant ramen? Of course, his mind pieces everything together and determines that the woman before him is the one most affected by Frisk's death. Undyne.

 

"Hey, Sans, wh-"

 

"papyrus killed frisk."

 

What? He panicked.

 


	2. Arc 2 Chapter 2

**Arc 2 Chapter 2**

 

_"Hey, Sans, wh-"_

 

_"papyrus killed frisk."_

 

_What? He panicked._

 

_ _ _ _ _ _ _ _

 

"Papyrus? That's funny, Sans," Undyne says, "but we both know he's too innocent to do something like that."

 

"it's true though. i don't want to believe it either, but i overheard a conversation between papyrus and that little weed, flowey. papyrus didn't seem normal. i think he actually did do it. he called himself a sociopath of all things," Sans explains.

 

"What's a sociopath?" Undyne asks, confused at what in Asgore's name the unfamiliar word meant. Furthermore, she wondered how Papyrus knew what it meant when she didn't.

 

"it means he just doesn't care about anyone even himself. he's apathetic about everything. indifferent," Sans explains. "it's a mental illness, and the more i think about it, the more it just fits."

 

The more he thinks about it, the more he finds it to be plausible. He just keeps feeling worse. Did he mess up? No matter how much he tells himself it's a mental illness, and he couldn't help it. He just wants to blame himself. He made some sort of mistake along the way. It's his fault. It's all his fault. He has to help Papyrus. Papyrus is his brother still. He can still try to help him, right?

 

Undyne is thinking about what was told to her by Sans. Papyrus? Papyrus of all people killed Frisk? Papyrus is the nicest monster in the Underground. A gullible and kind of stupid one, too. She would know. She's trained him for years now. Even if the Royal Guard was disbanded, she decided to cheer Papyrus up by continuing their training. Physical training and cooking both.

 

She thinks about the thing about him being sociopathic. About what it means. Has Papyrus ever just not cared? No. He's always cared. But Sans wouldn't lie to her about something like this. Not to mention he has literally ran into her. And he never runs. He's being serious. Completely serious. Papyrus killed her bestfriend. It was Papyrus. Frisk is gone because of him. Papyrus. Papyrus killed Frisk.

 

She's going to kill Papyrus. Her bestfriend is gone because of him, and now, he must die. He will pay for what he has done! She looks to Sans who seems lost in thought, and his eyes scream that he's conflicted. He doesn't know what to do. She thinks about the past few weeks. She's still hurt by losing Frisk, but she's really grown since then, hasn't she? Sans needs to go through this obstacle alone, but she'll give her support.

 

"Sans," she says softly, a reminder of what she has become, "I don't understand completely why your going through, but I'll give you some advice. Even though you're traveling this hard path alone, you have all your friends rooting you on, alright?"

 

Sans looks at her in surprise.

 

"thanks, undyne. that really kelped," Sans says. Even in times like this, he's making puns. She doesn't question it just this once. Everyone's minds process things differently. Perhaps his way of coping with all this are his horrid puns.

 

Sans has to find out how he's going to confront Papyrus about this. What is going to do?

 

***

 

Chara looks around. They're still not used to being on the Surface. And they're stuck here, too. They had decided to follow Frisk around upon being awoken. Then, all that stuck recently with Papyrus. They are upset. Angry. They didn't agree with Frisk a lot, but they had made a deal, and now, they're deprived of their only source of chocolate. What are they going to do now? Chara can't just take over somebody just to eat chocolate, right?

 

"I suppose I could. That would work actually," Chara reasons. They just need to find somebody to take over now. They float through the graveyard and out of it. As they look around, they see the perfect body. What could be better? Plus, it's a win-win situation.

 

They take over Flowey's body. There's a shriek of surprise from Flowey. A glow emanates as the flower body is shredded into pieces and the dust that had been from a long-dead prince forms a less dead prince. Asriel Dreemurr. Asriel looks at their body in surprise. Not only does he have a body but he can feel things.

 

"Hey, Asriel. We're going to go get Papyrus back for killing Frisk," Chara says out loud.

 

"Huh?!" Asriel exclaims. "Chara? But how?! I… what? I… I can't do that!"

 

"You can," Chara informs him. "You just don't want to, but that's not the case either."

 

"I don't want to hurt anyone," Asriel whispers as if he's afraid talking too loud will make this form disappear. He doesn't want to be Flowey again, especially after just getting this form back.

 

"I'm not afraid to. He's a threat to monsterkind, isn't he? We have to stop him at all costs," Chara claims.

 

"Wait! What do I do?! Where do I go?" Asriel asks.

 

"Leave everything to me," Chara says. "You trust me, don't you?"

 

The small goat looks down at his small, furry hands. He thinks of that day many years ago when he and Chara fused and crossed the barrier. Chara wanted him to fight back, but he refused to. He just walked back without a word. The humans were confused and scared. They thought he had killed Chara. He understands the humans' misconception. He did just walk into their village all of a sudden, holding the body of a child. Anyone would assume the worst.

 

"Asriel?" Chara calls out, worried about their brother.

 

"Yeah. I trust you. I guess we have a lot of catching up to do, don't we?" Asriel points out.

 

"Yes, we do, Asriel," Chara responds. "Yes, we do."

 

"You can tell me about while we walk, alright, Chara?" Asriel informs their sibling.

 

"Alright. Well, it all started with…," Chara starts and tells the tale of their adventures after awakening as a ghost. How they met Frisk. How they just didn't understand Frisk at all. How they don't understand how someone who got bored and committed genocide could be so much morally better than them. How can a killer have better integrity than them?

 


	3. Arc 2 Chapter 3

**Arc 2 Chapter 3**

 

Recap:

 

_"Yeah. I trust you. I guess we have a lot of catching up to do, don't we?" Asriel points out._

 

_"Yes, we do, Asriel," Chara responds. "Yes, we do."_

 

_"You can tell me about while we walk, alright, Chara?" Asriel informs their sibling._

 

_"Alright. Well, it all started with…," Chara starts and tells the tale of their adventures after awakening as a ghost. How they met Frisk. How they just didn't understand Frisk at all. How they don't understand how someone who got bored and committed genocide could be so much morally better than them. How can a killer have better integrity than them?_

 

_ _ _ _ _ _ _ _

 

A new Ambassador of Monsters is needed. Frisk had been the ambassador before. However, they have tragically been taken from this world and no longer have the ability to be the ambassador. A new one will need to be sought out. Who would be a good candidate though? Alphys? Papyrus? Undyne? Undyne really seems like a good idea. Maybe she would be interested.

 

Asgore leaves to look for Undyne, but after much searching, he is unable to find the woman. He does however run into a ghost monster.

 

"Oh… um, I'm sorry. I should go," he apologizes.

 

Asgore smiles, "It's okay. I should have been watching for where I'm going."

 

"It's alright," Napstablook responds.

 

Asgore looks at the ghost. He doesn't know why, but he feels better about himself around the ghost. Not to mention, he's kind and humble. Could this be fate giving him a sign? He had been looking for Undyne but instead he found…? Who is this guy anyways? He looks kind of familiar.

 

"Excuse me but what's your name?" Asgore asks the incorporeal ghost.

 

"Oh… I'm Napstablook," the ghost answers.

 

Asgore thinks his choice over. Is he sure? Would this ghost be ambassador material? Not just anyone can be the Ambassador of Monsters. Perhaps he could test him.

 

"Would you say you understand politics?"

 

"…I guess?"

 

That does it.

 

"You're hired."

 

"Oh… Uh, I mean, I guess that's alright but what for?"

 

"You're going to be the new Ambassador of Monsters."

 

There's a silence.

 

Napstablook had been on his way home. However, he had bumped into the former King of Monsters. He didn't think he would. Although, he didn't particularly think he wasn't. But he certainly didn't think he would. Nobody would expect to run into the King of Monsters, former or otherwise, on the streets on their way home. Then, he's suddenly being told he's the new ambassador. He confused and too awkward to tell Asgore that he'd be the best choice for ambassador.

 

"Oh," Napstablook responds, "okay…?"

 

***

 

Alphys is stress working. Ever since the incident with Frisk, Alphys has been extra worried about Undyne. The two were close, and Alphys knew this. It was Alphys's job as Undyne's girlfriend to keep her happy. At least, that's how she felt. Alphys has been so worried about Undyne and sad about Frisk too that she's been throwing herself into her work. She doesn't want to think about all the problems. And working uses up all of her attention.

 

Mettaton has been really worried about Alphys recently. He knows of Alphys's tendency to get easily overwhelmed. He knows Alphys well. He knows Alphys has social anxiety. He knows she's an awkward little monster. He knows she can get really upset about some things. He knows she has existential crises. He knows her so well. And he really worries about her. Alphys is almost like a mother figure to him. She had built him this body, so she is one in a way.

 

What choice does he have but to be worried? If he won't, who will? Undyne has been busy as of late and is oblivious to the extent of Alphys's insecurity. Sans will come by and talk sometimes but not enough. Papyrus, if he does come, asks about any new puzzles; he's always nice to have around.

 

Speaking of Papyrus, he feels like something is off about the skeleton. He's not exactly acting in any way that may attract unwanted attention as far as he's aware. That's what worries him. Papyrus doesn't seem affected by the loss of Frisk at all! Is he bottling up his feelings? Papyrus is known for being a ray of sunshine and a ball of energy; he certainly doesn't seem the type to keep his feelings to himself. Maybe he's just over thinking things though.

 

***

 

i know what you did, you dirty brother killer… killer, Sans thinks.

 

No. That's just stupid. He needs to confront his brother about all this. It's been a while since he overheard that conversation. It's been a while since he accidentally told Undyne about Papyrus. Now, that he can just sit and think about it, that was a bad move on his end. He shouldn't have been eavesdropping on Papyrus in the first place. Much less told Undyne. He can't undo any of that though.

 

Sans groans and curls up into a ball. Tears of frustration form at his sockets. Why can't things go his way? Why can't life just let him win? Is it such a bad thing for something to go right in his life? He just wants everything to go back to normal. He wants Frisk back. He wants his brother back.

 

"is that too much to ask…?" Sans inquires rhetorically. It's a question asked of life or fate or whatever force is screwing his life over. He just wants to be happy. He wants his brother to be happy.

 

"IS WHAT TOO MUCH TO ASK?"

 

Sans looks up in surprise. He doesn't even bother to wipe away the tears streaming down his face. His brother. He had been avoiding him actually over the past few days. If Papyrus really can't care about people, why does he act like it?

 

"my life back."

 

"WOULD YOU LIKE TO TALK ABOUT IT, BROTHER?"

 

Does he? Yes. Can he? He's not sure, but…

 

"yeah, bro."

 

Papyrus waits expectantly.

 

"i overheard your conversation the other day with that flower."

 

Papyrus pieces things together. Oh. OH. That explains a lot recently actually.

 

He asks, "What do you think of me now?"

 

"i just want to keep my little brother safe."

 

"Then, help me."

 

"…okay."

 


	4. Arc 2 Chapter 4

**Notes for the Chapter:**

> Warning: Character Death

**Arc 2 Chapter 4**

Recap:

 

"i overheard your conversation the other day with that flower."

 

_Papyrus pieces things together. Oh. OH. That explains a lot recently actually._

 

_He asks, "What do you think of me now?"_

 

_"i just want to keep my little brother safe."_

 

_"Then, help me."_

 

_"…okay."_

 

_ _ _ _ _ _ _ _

 

Undyne waits in the field. This field is the new training area she and Papyrus agreed on. She has a plan. And it'll work. She's getting help from a little goat monster, too. She doesn't know how he knows about all this or why he looks like the dead prince, but she doesn't care. She needs all the help she can get. She had sent the little goat monsters out to remind Papyrus of training. She hopes he'll be okay.

 

Even when they said they'll be alright, she's unsure. They were a child after all? She's starting to question her decision. Did Papyrus kill them? Sans would find out something like that, wouldn't he? Did Sans know the whole time? No. He wouldn't have told her if that were the case or would have informed her sooner. And he was panicked the other day when he told her. He was just as confused as she by the whole ordeal. He's not stupid. Lazy, yes but not stupid.

 

Undyne is about to go after the child, getting anxious when she sees three figures. She squints and sees Sans walking beside Papyrus. She's almost worried, but she sighs in silent relief upon seeing the small goat monster. The kid is alright. They are eventually in front of her. She crosses her arms and grins widely, putting up a tough act. He's right before her. He's right there. The one who killed them is in front of her; Frisk's murderer is standing right in front of her.

 

"Are you ready for training, Papyrus?" Undyne asks darkly. If he noticed, he didn't say anything.

 

"OF COURSE, UNDYNE!" the ever-excited skeleton proclaims with an overly happy smile as usual. He's right there. But did he really kill Frisk? How could this guy have killed Frisk? No, Sans said it himself. Undyne has to be the hero. She has to protect the innocent life that are threatened by this evil. Undyne has always wanted to be a heroine; now is her chance. She will protect them all. Nobody will be subjected to the same fate as Frisk.

 

She summons a spear into her hand, bright and glowing and green. She looks to Sans briefly who seems… off. Something isn't right. She'll figure that out later though. She has to defeat Papyrus. She throws the first spear and the battle begins. Many bones and spears are thrown about. The war cries from either sides can be heard. To certain special people, the clashing of theme songs can be heard. It's quite the sight to behold.

 

Undyne keeps going, making moves to kill unlike what she would normally do in training. As if suddenly realizing what Undyne is doing, Papyrus swipes a bone swiftly and precisely. Undyne turns to dust.

 

Asriel watches blandly. He knows -- even Chara knows -- that Undyne is more determined than just that. She'll come back. She'll be harder to defeat, better in battle, faster at throwing those spears, and over all stronger. Undyne will have a newfound resolve. She will come back. She'll keep going. Undyne will be DETERMINED. Determined to serve justice. Determined to win.

 

Just as they predicted, Undyne's ashes reform. Undyne is determined. This isn't just Undyne anymore; this is Undyne the Undying. She is the heroine that will defeat all evil. Undyne releases a mighty roar, "NGAAAAAAAAH!"

 

Asriel wants to help, too. Chara joined him to torture Papyrus, so that's what they're going to do. They're going to get revenge. They are DETERMINED!

 

Sans is still just standing there, watching Undyne and Papyrus now fact off. This is their battle to the death. Only one side will leave alive. He's unafraid as he sidesteps a stray spear. Most monsters don't dodge; most monsters can't dodge. Finally, as if only just then realizing a battle is going on, he attacks Undyne as well. Asriel blocks it with a summoned sword, now being the God of Hyperdeath. He and Undyne will be victorious.

 

"You know, don't you?" Asriel accuses Sans. "You know Papyrus killed Frisk. You just don't care."

 

Sans says nothing. Perhaps he didn't hear it at all, but two more theme songs that only the certain special people can hear begin to play. Sans and Asriel begin their battle to the death as well.

 

***

 

"Why can't you just die already?!" Undyne exclaims in fury. Her spears are expertly blocked by Papyrus.

 

"Frisk had reason to die, and I feel no remorse," Papyrus states coldly. It sends a shiver down Undyne's spine. She gnashes her teeth and growls.

 

"That's because you're a sociopath!" she yells in frustration.

 

"Yes, that is true. That is indeed what the doctor told me," Papyrus agrees as if the two are taking a casual stroll through the park.

 

"You're really pissing me off," Undyne warns him. Honestly, she's already angry, vehemently so. She has been angry this whole time too, and seeing him now is just making her madder.

 

"You're not pissing me off," Papyrus tells her with a shrug of indifference.

 

Is he crazy? Does he have a death wish? That was sarcasm. Sarcasm. From Papyrus. Undyne has known Papyrus for years now, and he doesn't use sarcasm. Ever. Now, he does. And she's absolutely offended. She wants to throttle the skeleton for mocking her.

 

"How dare you!" she yells. She takes a breath and repeats the same phase but in a whisper, "How. Dare. You."

 

She explodes into laughter as she sends out multiple waves of spears from all over as fast as she can.

 

Papyrus doesn't move even when multiple spears hit him. Undyne stops abruptly and frowns. He asks, "Is something wrong, Undyne?"

 

He doesn't both removing the magical spears. He fells them. He really does. He just doesn't care. He doesn't care about Frisk or that they died. He doesn't care about the goat monster that's fighting with Sans. He doesn't care about Undyne. He doesn't care about himself either. He doesn't even care about his brother. He simply exists. He's just there.

 

***

 

Sans dodges another attack. He can don't his. He can win. His brother will win. His brother will survive. He doesn't have to worry about failing his brother ever again. He's doing the right thing, right? Yes! Protecting his little brother is always the right thing. Protecting his brother is always first priority. Papyrus must live. Papyrus is all that matters. He'll always support his little brother no matter what.

 

It's the others that are wrong. He won't listen to them. He won't talk to them. He won't interact with them. He won't care about them because his brother can't care about them. He has to help his little brother. He has to help Papyrus. He just wants Papyrus to feel. He wishes Papyrus could feel. He'd gladly take up then role of being an emotionless person if it meant Papyrus could be happy.

 

He summons some bones and attacks. Swift and efficient. Just get the job done. Dodge. Their soul is blue now. He throws the monster around this way and that. He avoids a variety of obstacles, mostly star-based ones. More bones. This seems like it'll go on forever. There's something about the monster that seems like they only partly want to fight him. He's getting tired, but that doesn't matter. Papyrus is his lifeline. He has to stay awake. He has to stay alive.

 

He has to finish this battle quickly.

 

He has to win this battle quickly.

 

How? And then, he sees Undyne going for the kill, but Papyrus has the same idea as the blue woman. With just a little focused magic, Sans turns her soul blue. Papyrus lands a final blow. She's trying desperately to hold onto life. She's changing from whatever a magical body would be considered to more of the consistency of glue. It's disgusting. She can't even fight back, not properly anyways.

 

It's pitiful.

 

It's sad.

 

Unlike Papyrus, Sans feels guilt. Guilt that he helped kill her. She had been one of her friends once. Up until today. He doesn't realize the tears falling from his eye sockets. He doesn't realize he's quivering. He doesn't realize it when he blacks out.

 

**Notes for the Chapter:**

> Well, then. This took a couple weeks to write, but Arc 2 is over. Sometime, I'll have to give the characters differences to, well, differentiate them from other AUs. I'll do that in Arc 3.


End file.
